Arthralgia, joint pain, is emerging as a major source of symptom burden in postmenopausal breast cancer survivors receiving Aromatase Inhibitors (AIs) as adjuvant therapy. Data from large clinical trials suggest that AIs increase the rate of arthralgia by 20 to 30%. A recent study found that 47% AI users in an outpatient oncology practice reported AI-related arthralgia. Arthralgia not only impairs daily functions but can also lead to non-adherence and premature treatment discontinuation, both of which seriously diminish the effectiveness of AIs for prevention of breast cancer recurrence. As a promising non-pharmacological approach to pain management, acupuncture stimulates the central nervous system's production of endogenous opioids, which may be decreased in AI users because of estrogen depletion. While several clinical trials have demonstrated the efficacy of acupuncture for osteoarthritis of the knee in the general population, no randomized controlled trial has investigated its effects on AI-related arthralgia. Building on our existing pilot work, this R21 proposal seeks to bring together a multidisciplinary team of investigators to rigorously and systematically evaluate the effects of an 8-week of electro-acupuncture (EA) intervention for AI-related arthralgia among 75 postmenopausal women with stage I-III breast cancer, who have completed primary treatment (surgery, chemotherapy, and radiotherapy), and who are currently receiving AI therapy. This will be accomplished in a 3-arm parallel, randomized, controlled trial comparing EA against wait- list control (WLC) and placebo EA (delivered using the Streitberger non-penetrating needles). Our specific aims are: 1) To determine the overall effect of acupuncture for reducing AI-related arthralgia by a comparison between acupuncture and WLC;2) To estimate the effect size and variance between verum and placebo EA to be used to power the follow-up R01;and 3) To elucidate the relationship between response expectancy measured by the Acupuncture Expectancy Scale and clinical response to acupuncture defined as percent reduction of pain at the end of the intervention. The above specific aims will allow us to generate the necessary data to plan a definitive R01 that aims to establish the efficacy of specific acupuncture needling for reducing AI-related arthralgia. PUBLIC HEALTH RELEVANCE: Because arthralgia is a major symptom burden negatively impacting many breast cancer survivors taking aromatase inhibitors, effective interventions need to be identified and tested. Women with breast cancer are widely interested in using non-pharmacological approaches for symptom management. Therefore, the study of acupuncture for this application has the potential to provide the much needed evidence that acupuncture may reduce pain and improve quality of life among hundreds of thousands of women.